This invention relates to compensating harmonics in general and more particularly to a circuit for compensating harmonics in an electric consumer arrangement, particularly high voltage d-c transmission systems.
Filter circuits for compensating harmonics which include an L-C-R series resonant circuit in at least one loop are known. In such circuits, such as are provided particularly for high voltage d-c transmission systems, undersirable harmonic currents can be transmitted to d-c consumer arrangements from the converter stations which are connected to the latter via high voltage d-c (HVDC) lines, unless these harmonics are removed from the HVDC lines by filter circuits. These harmonics must be avoided, for instance, because of interference with a connecting telephone line. For higher harmonics, this can generally be done successfully by means of appropriate highpass filters to a sufficiently high degree, but the difficulty of reliably reducing the line current in dependence on the temperature, for instance, for eliminating harmonic currents of low order (for instance, the 12th harmonic in 12-pulse groups) remains.